Kumar and colleagues performed a large-scale multicenter retrospective study including more than 1000 COVID-19 patients and found that bradycardia was prevalent and associated with higher mortality among them.¹ Their findings are of great interest because infection and high fever are, in general, associated with tachycardia. Several concerns have been raised.

To further clarify the mechanism of COVID-19 associated bradycardia, it is of great interest to investigate the type of bradycardia: sinus bradycardia, AV block, or atrial fibrillation. Noncardiac causes should be carefully excluded, including sedation, conduction-suppressive medications, and hypothyroidism.

The causality between bradycardia and mortality remains unclear. Bradycardia might be a marker of the advanced stage of COVID-19 or a direct cause of death. Bradycardia might be more prevalent in patients with COVID-19 associated myocarditis with incremental troponin level. On the other hand, bradycardia might cause low cardiac output accompanying cardiogenic shock. If bradycardia is harmful, aggressive intervention to bradycardia, including pacemaker therapy, would be beneficial. In their study, was the dominant cause of death in patients with bradycardia respiratory failure or heart failure?

Kumar 及其同事进行了一项包括 1000 多名 COVID-19 患者的大规模多中心回顾性研究，发现心动过缓很普遍，并且与更高的死亡率相关。¹他们的发现非常有趣，因为感染和高烧通常与心动过速有关。已经提出了几个问题。

为了进一步阐明 COVID-19 相关心动过缓的机制，研究心动过缓的类型非常有趣：窦性心动过缓、房室传导阻滞或心房颤动。应仔细排除非心脏原因，包括镇静、传导抑制药物和甲状腺功能减退。

心动过缓与死亡率之间的因果关系尚不清楚。心动过缓可能是 COVID-19 晚期或直接死亡原因的标志。在肌钙蛋白水平升高的 COVID-19 相关心肌炎患者中，心动过缓可能更为普遍。另一方面，心动过缓可能导致伴随心源性休克的低心输出量。如果心动过缓有害，积极干预心动过缓，包括起搏器治疗，将是有益的。在他们的研究中，心动过缓呼吸衰竭或心力衰竭患者的主要死亡原因是什么？